Since 2001, Benchmark Carbide has improved its performance and received good marks for its patented end mills, resulting in dramatically increased demand from its customers. To keep up with that kind of demand, Paul St Louis, company owner, has invested in 27 ANCA CNC tool and cutter grinders with automatic loaders. “We run our ANCA’s 24 hours a day, seven days a week, producing primarily end mills. Aerospace is a key customer industry,” Paul remarked.
It is a neatly organised and compact shop. “Every machine is robotically loaded and we run a lean shop. Double wheel packs on twin spindles and in-machine dressing on the ANCA’s means we have flexibility and the capability to operate long hours unattended, producing superior tools without interruption.”
Production-oriented TX7’s with auto loaders run larger tools to 1.5”, RX7’s run the smaller tools from .006 to .500”. The automation and lean shop organisation permit Benchmark to operate as a low cost producer and to offer the market some highly innovative tool designs that reduce the cost of machining aluminium and other materials.
The TX7’s feature a powerful 49-HP 10,000 RPM spindle, an automatic wheel changer, auto-loading system, and a 3000 RPM headstock. ANCA’s ToolRoom tool and cutter grinding software drives the machine. It is a complete changeover of wheel pack, coolant delivery system, workholding collet and pallet in less than 3 minutes. Other brand machines require 15-20 minutes to several hours for changeover to produce another type of tool. For the TX7, wheel packs and corresponding coolant manifolds are prepared off-machine and quickly exchanged to grind a new tool.
Innovative end mill line
Its customers look at Benchmark as innovators. It makes end mills for machining aluminium a little differently than others do. And they work exceptionally well, outperforming others. Most tools by other manufacturers are made with a cylindrical margin, where the shank is the OD of the tool that is cutting. End mill makers typically flute it out and leave behind a narrow—often .003 wide—margin. This is often difficult to hold. If it is too wide, it will push away; too narrow, you get chatter.
“With our ANCAs, we grind 3 grinds on the OD: primary, secondary and a ground-on edge prep, which reduces chatter and vibration and we can control the thickness of it to .0015 and .002 wide. So when the tools are milling aluminium, they do not squeal or chatter. Machining is consistent and high quality. The tool repeats and we have two grinds on the fluting to move the chip a little better,” Paul said.
The company makes 2-, 3-, 4- and 5-flute carbide tools for high-speed machining of aluminium. Variable helix mills are a Benchmark specialty, starting with a 45-degree helix and ending at a 60-degree helix. The helix design reduces vibration in the tool. “With the ANCA’s producing 5-flute tools we can remove .0001” per tooth and over 50% of the tool diameter. With that tool in a 10000 rpm machining centre spindle you could run 500 ipm,” Paul pointed out. The edge preparation by Benchmark goes around the radius and does the end in a single grind. The machine and software capability lets Benchmark maintain its edge. ANCA ToolRoom software is key to allowing Benchmark produce the variable helix.
The direct drive, high-speed 3000 RPM work head (A axis) of the TX7 allows users like Benchmark to include cylindrical grinding operations in the tool grinding process without changing the set up, and to fully grind stepped or tapered blanks to the final tool. This means tools can be produced complete in a single set up, minimising production time for many tools that formerly may have required two operations to complete.
The ANCA TX7’s at Benchmark use the patented Big Plus wheel mounting system, which contributes to high precision running of the grinding wheels. The system, superior to a conventional tapered holder, provides a more complete and concentric contact plus flange contact. The resulting rigid assembly nearly eliminates runout and deflection, and benefits wheel life, surface finish, and part tolerance.
Mounted to the back of the chuck on the TX7s’ high-speed work head, the dresser roll is easily accessed or introduced to the wheels with minimal axis strokes for in-process dressing. The TX7’s the loader is mounted to the left of the machine and has its own control panel to enable quick, safe set up requiring only one operator. The loader brings the tool into the machine on a pneumatic carriage while the headstock automatically positions itself to receive the tool in a rapid tool change cycle.
The CNC wheel changer on the TX7s allows Benchmark to apply two wheel packs to one application, accomplishing more operations in a single set up. Mounted on a manifold, coolant piping changes with the wheel packs, so that coolant flow is always tuned to the wheel in use for optimum coolant application.
The RX7 also features a single direct drive multi-directional spindle with dual wheel packs positioned at either end of the spindle. The configuration of these wheels give complete unrestricted access to the workpiece. The spindle has a peak power of 19 kw and maximum speed of 12,000 RPM, suitable for the smaller range of tools at Benchmark. It also has good power at low speed with its highest power at 3600 RPM--very well suited to carbide grinding, according to Paul. Also with loaders, the RX7s help keep production moving at the tool maker.
Software is the key
Clayton Pirie manages the ANCAs at Benchmark. He says that he is always learning as ANCA is constantly enhancing its software and promptly provides the updates to the shop. “ANCA’s user friendly software has enabled us to produce a number of innovations that other tool makers just don’t,” said Pirie. “The CIMulator3D lets us lay out the whole tool off-line without wasting grinding machine time. We can dream up a tool and see if we can make it before we ever get to machining. It’s an innovator’s best tool,” he added.
ANCA’s CIMulator3D® provides an off-line tool development environment, which enables the efficient design of new tooling and the required manufacturing process, avoiding loss of production. Set up time for new tools is dramatically reduced, and production can begin more quickly. As an offline workstation, CIMulator3D can also be run on the CNC to simulate tool production programs before grinding.
“When we did half the volume, it seemed more stressful on the shopfloor. Today, there are only three set up people in each shift, yet it’s a calmer atmosphere. We are producing much more with much less stress, thanks to the ANCAs. The machines are doing consistently high quality work over long runs,” observed Paul.
The article is reproduced with courtesy to ANCA CNC Machines